Unveiled at the 2012 CES to a receptive audience of battery-drained iPhone 4/4S users, Incipio's finally-released OffGrid Pro ($100) isn't the first case we've seen with the ability to swap rechargeable battery packs, but it's a very polished implementation -- one that we found highly worthy of our 2012 Best of Show Award. Based upon the original OffGrid design, this one is only 0.03 inches thicker despite that fact that it houses a higher capacity, removable battery. Also impressive is what Incipio includes in the package for the price. Not only do you get the case, a battery, and a Micro-USB cable, but a second battery is included as well, plus an external battery charger and headphone extender. It's worth noting that when we first saw the battery pack in January, it came with two 1700mAh batteries, but it now ships with slightly smaller 1600mAh cells.

The case component of OffGrid Pro separates into two plastic pieces: a rear sled with a Dock Connector plug onto which the iPhone slides, and a frame that snaps over the iPhone’s sides for protection. Given the capacity, it’s surprisingly thin, adding only a modest bump to the iPhone’s flat back. Inserting the device is simple, as is snapping on the frame—for the most part. With both the black and gunmetal versions, we had no problem putting the bumper in place, and it’s just as easy to remove. The white version was a different story, though: for some reason, the frame was extremely tight, and took much more force to install and take off. Later attempts became somewhat easier, although there was still a noticeable difference between the colors; it was always harder to get the white frame off. When the iPhone is removed from the case, the small, rectangular battery is fully accessible. A divot above it allows it to be lifted right out and replaced when necessary.

We were impressed by how much coverage OffGrid Pro offers; it’s more protective than most plastic cases, including the original OffGrid. The iPhone’s edges are almost fully covered, including the Sleep/Wake and volume buttons—a rarity with plastic cases, and they still feel quite responsive to presses. Otherwise, there is a cutout for the side switch, another for the speaker on the bottom edge of the phone, one for the noise-canceling microphone, and a very small hole around the headphone port—likely sized this way to maintain structural integrity. Apple’s headphone plugs fit just fine, but for those who use headphones with larger plugs, the included extender is a nice solution. As for the camera, Incipio utilizes dual flash diffusers, with one ring around the camera itself and another around the flash, both recessed beneath the gradients of one large hole.

In addition to everything else, there’s a Micro-USB port on the bottom edge, directly above a hole that acts as a passthrough to the microphone, allowing the iPhone and the extra battery behind it to be charged in the case. Unfortunately, the case rests completely flush against the edge of the screen, providing no lip to protect it in case of a fall. Directly below the Home button is a combined power toggle/battery indicator button; pressing it quickly reveals how much charge is left, with up to four blue LED lights showing the remaining power. Holding it for a few seconds turns the power on or off.

One of the coolest parts of the bundle is the external battery charger. It’s quite simple, but there’s no need for it to be complex. At 4"x2” and just 3/8” thick, it feels about as small as it can be, and actually fits inside of the case for storage when neither are in use. It’s primarily made out of hard black plastic—regardless of which color case you choose—with a recession perfectly sized for the spare battery. The bottom is lined with rubber, which helps prevent it from sliding around your desk. Along the edge is a Micro-USB port, and there’s a single LED charging indicator on the chin directly beneath where the battery sits. Since Incipio only packs in one Micro-USB cable, you’ll have to provide your own if you plan on charging the battery in the case and the extra at the same time, but the fact that you have options for the price is awesome.

With everything else executed so well, we had high expectations for the key element of the case: its battery performance. Comparable batteries, including Mophie’s 1500mAh Juice Pack Air and the 1450mAh cell in the original OffGrid, were able to juice up an iPhone by 70% and 63%, respectively. Naturally, we anticipated that the slightly larger 1600mAh capacity would mean more power. Incipio’s packaging even states that OffGrid Pro will triple an iPhone’s battery life, suggesting performance of up to 100% from each battery, plus the iPhone’s own charge. We were therefore surprised and a little disappointed to discover that two separate batteries were each only able to provide a 64% charge before becoming depleted. This result came from testing on the same iPhone 4S under our standard conditions, with the screen off, Wi-Fi and cellular connections active, and no media playing. It’s important to keep in mind, however, that you’re still getting 3200mAh of power for $100, plus the ability to add additional cells at any time—a good deal compared to paying $70-$80 for a less capable model mentioned above.

Understanding OffGrid Pro’s appeal is fairly easy: for $100, you get 3200mAh of power in a slim, thoughtful form factor, plus two options for charging. The individual cells’ battery life isn’t as impressive as what we expected from CES, but everything else is pretty much spot-on. The case itself is protective and attractive—save for the frame-related issues we saw with the white model—with a simple hot swapping process, and the extra charger as a really nice bonus. It’s unclear why the batteries fell short of expectations, but considering that Incipio provides the tools to have one at the ready when it comes time to change them, this isn’t as big of a deal as it might be for a case with a non-removable battery. All things considered, you’re still getting the ability to charge your phone to at least an additional 130% for a very fair price, inside a generally great form factor—for these reasons, OffGrid Pro is worthy of our high recommendation.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.